1. Field of the Invention
The present invention relates to a portable terminal, an in-vehicle apparatus installed in a vehicle, and a navigation system including a portable terminal removably mounted in the in-vehicle apparatus.
2. Description of the Related Art
A navigation apparatus detects the location and orientation of a vehicle by using a GPS (global positioning system) or the like. Map data corresponding to the vehicle location is read from a map-data storage medium, such as a hard disk, CD-ROM, or DVD-ROM, on which a large amount of map data is stored. Based on the read map data, a map image of the vicinity of the vehicle location is displayed on a display device with a vehicle-location mark being superimposed on the map image. The map image is scrolled as the vehicle travels, so that a user can recognize the vehicle location.
A known navigation apparatus has a route-guidance function so that the user can drive a vehicle to a destination without getting lost. In the route-guidance function, using the map data, a guidance route having the lowest cost of a route that connects a start point to a destination is automatically searched for using a simulation calculation involving a breadth-first search method, Dijkstra method, or the like. A found route is stored as a guidance route. During travel of the vehicle, the guidance route is drawn, on a map image, in a different color from that of other roads and/or in boldface. When the vehicle approaches within a predetermined distance of an intersection where the vehicle is to change traveling direction on the guidance route, an arrow indicating the traveling direction may be displayed at the intersection, to thereby guide the driver to a destination.
There is also a known navigation apparatus that is installed in a vehicle to perform route guidance of the vehicle and that is also removable therefrom for hand-held use to perform route guidance of the user. With such a navigation apparatus that can be used after being removed from a vehicle (e.g., the technology disclosed in Japanese Patent Application Publication No. 2005-207934), when the navigation apparatus is removed from the vehicle while performing route guidance and is then re-installed in the vehicle after being used as a hand-held device, it is possible to return the operation to the route guidance operation performed before the removal.
In recent years, portable audio players are widely used, and the above-described navigation apparatus that can be used after being removed from the vehicle may also have an audio-playback function. In such a case, there is a need to appropriately switch the route-guidance operation and the audio-playback operation between the state in which the apparatus is mounted in the vehicle and the state in which the apparatus is used as a hand-held device.